3-D Contour Plot Command
------------------------

AUTHOR:   Gerard van de Kuilen
	  Oasis Decision Support Systems
	  The Netherlands
SUPPORT:  FAX, +31-3402-65844
	  
                     ^plot3d^ function(x,y)
          Example:   ^plot3d^ sin(x)^^2 - cos(y)^^2^

where function is a valid Stata expression. There should be no data in memory 
when calling the command.  ^plot3d^ creates a 3-d contour plot; but since 
contour plots necessitate overlaying, you must have Stage in the current or 
path directory.

Three programs are involved in contour plot production: ^plot3d.ado^,
^plot3d.prf^, and ^stage.ado^. These should be in the current directory
or in an ado-directory; however, the prf-file must be in the current
directory. If it is not, ^plot3d^ will not work.

The z-axis is vertical, the y-axis is horizontal, and the x-axis
is "coming out of the paper."